Vitreous haemorrhage is bleeding into the jelly-like filling of the back part of your eye. This substance is the vitreous humour. It helps the eye keep its shape and is normally clear, allowing light from outside the eye to pass through it to reach the retina.
Vitreous haemorrhage varies in degree from mild, with 'floaters' and haziness in the vision, to complete loss of vision. It is painless and it comes on quite quickly. Usually only one eye is affected. Whilst it is very alarming, once the bleeding has been treated, many cases resolve and vision is restored to where it was before.
What is vitreous haemorrhage?
Vitreous haemorrhage occurs when blood leaks into the vitreous humour inside the eye. The blood most commonly comes from blood vessels at the back of the eye. These can be either of the following:
- Normal blood vessels which have been damaged.
- Fragile abnormal blood vessels which have grown at the back of the eye and which bleed very easily.
In order for us to see clearly, the vitreous humour needs to be clear. If the vitreous humour is clouded or filled with blood, vision will be impaired. This varies from a few 'floaters' and cloudiness of the vision through to the vision going completely dark (sometimes with a reddish tinge).
Who is likely to experience vitreous haemorrhage?
The most common cause of vitreous haemorrhage is severe diabetic eye disease, which is mainly seen in older adults. The common causes of vitreous haemorrhage tend to occur in adults aged 60 and above, except for eye trauma, which can occur at any age.
What is the vitreous humour?
The vitreous humour is a clear jelly-like substance that makes up about 80% of the volume of the globe of the eye. It supports the shape of the globe of the eye whilst letting light through. It is made up mainly of water but with some collagen and hyaluronic acid. The outside is made of fine fibres which are attached to the retina at the back and to the back of the lens at the front.
How common is vitreous haemorrhage?
Vitreous haemorrhage affects about 7 per 100,000 people each year. This makes it one of the most common causes of sudden deterioration in vision. It most often affects only one eye.
What are the causes of vitreous haemorrhage?
The most common causes, accounting for about 90% of all cases, are:
- Bleeding from abnormal new blood vessels forming in advanced diabetic eye disease.
- Bleeding from tears in the retina caused by vitreous detachment (see below).
- Trauma to the eye (the most common cause in younger people).
Bleeding inside the eye can come from:
- Abnormal blood vessels which grow because the back of the eye is short of oxygen. These are fragile and bleed easily. Conditions in which this can occur include:
- Diabetic eye disease (the most common cause).
- Macular degeneration.
- Retinal vein occlusion.
- Retinopathy with sickle cell disease.
- Damage to the back of the eye in very premature babies who have been on oxygen in special care baby units.
- Normal blood vessels which are damaged. They may be damaged by:
- Posterior vitreous detachment, often with a retinal tear (see below).
- Retinal macroaneurysms - swollen blood vessels on the retina, usually related to high blood pressure, atherosclerosis and smoking.
- Blunt trauma - suddenly compressing the eye - for example, if hit by a squash ball.
- Penetrating trauma - this will cause bleeding throughout the eye.
- Subarachnoid haemorrhage, which can increase the pressure in the veins in the retina, causing them to bleed.
- Surgery to the eye.
- Blood from behind the retina tracking through into the eye. This is the least common cause of vitreous haemorrhage. It may result from:
- Tumours of the back of the eye (most commonly ocular melanoma).
- Fragile new blood vessels behind the retina.
Posterior vitreous detachment is usually experienced between the ages of 60 and 80 - it happens to most of us between those ages. It occurs when the vitreous pulls away from the retina at the back. This can happen quite suddenly as the vitreous tends to shrink with age. Most commonly there are no symptoms. Sometimes posterior vitreous detachment causes bleeding from the retina as it pulls away. Sometimes the retina is torn as the vitreous pulls away from it.
Most people experience posterior vitreous detachment in their 60s or later, and most do not have significant vitreous haemorrhage. However, episodes of noticeable floaters are very common and these represent small bleeds.
What are the symptoms of vitreous haemorrhage?
The symptoms of smaller bleeds (which most are) are of floaters, cobwebs, haze and shadows in the eye. There may be a red tint to the vision. Symptoms most commonly affect one eye only, although both eyes can be affected.
More severe bleeds will cause haziness of vision, sometimes with blind spots or dark streaks. However, the most severe bleeds will cause visual loss, which can be complete. This is extremely alarming, particularly as it tends to come on very quickly with no clear explanation.
How is vitreous haemorrhage diagnosed?
You will normally be examined with a slit lamp, a device used by opticians and ophthalmologists to look in detail at the inside of the eye. The slit lamp will allow the examiner to see the blood in the vitreous.
Finding the source of the bleeding may be possible with the slit lamp, although if there is a lot of blood in the vitreous humour this prevents a good view and it may therefore be difficult to know what has happened. In this case you may have an ultrasound scan of your eye. Ultrasound can detect many causes of vitreous haemorrhage, including posterior vitreous detachment, retinal tears and detachments, tumours and foreign bodies.
Sometimes an angiogram is needed. This test shows up the blood vessels in the back of the eye. This can be helpful if looking for abnormal blood vessels such as in diabetes.
CT scanning of the eyes is useful if there is a suspicion of a penetrating injury.
What is the treatment for vitreous haemorrhage?
The treatment of vitreous haemorrhage varies with the cause. Aims of treatment are to:
- Find the source of the bleeding.
- Stop the bleeding.
- Repair any damage to the retina before it results in permanent loss of vision.
- Restore normal vision.
Once the source of the bleeding has been identified, treatment will depend on the cause. If there is not too much blood in the vitreous and the source of bleeding can be seen then it is treated. This means laser treatment to bleeding vessels and any other abnormal vessels, and repair to any tears in the retina. After this it is a matter of waiting for the blood to slowly clear. This can take several weeks.
You will be advised to avoid strenuous activity for several days at least, as this might dislodge clots and trigger new bleeding. You are also advised to sleep with the head of your bed elevated, as this allows the blood in the vitreous to settle into the bottom of the eye, out of the line of vision.
If the blood in the vitreous obscures the view and prevents treatment of the bleeding then the entire vitreous may be removed first. This procedure is called a vitrectomy. Doctors will perform a vitrectomy if they can't see the back of the eye, or if the view isn't good enough to treat the bleeding there safely.
Laser photocoagulation is the usual treatment for fragile abnormal vessels. Treating them both stops the bleeding and prevents later bleeding. Laser photocoagulation is also used in repairing damage to the retina, including retinal detachments.
Anti-VEGF injections aim to shrink abnormal new vessels which have formed in the eye. They are sometimes used in patients with diabetes, in addition to other treatments like laser photocoagulation and vitrectomy, in order to reduce bleeding.
Cryotherapy is also used as a treatment for retinal tears and retinal detachments.
Vitrectomy is removal of the vitreous humour completely, together with the membrane that surrounds it. This is done when there is so much blood in the vitreous that it is impossible to diagnose and treat the cause. Vitrectomy is also sometimes performed if the blood in the vitreous is clearing very slowly and vision remains impaired.
Waiting is commonly the chosen option once the bleeding has stopped. Most cases of vitreous haemorrhage do not require vitrectomy. The blood clears slowly from the vitreous, allowing light to pass through it again. If the underlying vision is undamaged then normal vision will be restored.
If you experience a vitreous haemorrhage then you will usually be seen by a specialist on the same day. This is because sudden loss of vision is considered an eye emergency. The aim is to ensure accurate diagnosis and to avoid permanent loss of vision which could occur if there is a retinal detachment behind the bleeding.
If you have had a vitreous haemorrhage there are some things you can do yourself:
- See your GP or optician, or attend an accident and emergency department, as soon as you reasonably can.
- Try not to panic - most vitreous haemorrhage responds well to treatment and there is a very good chance your vision will return to where it was.
- Rest for a few hours a day sitting upwards and elevate your head at night on pillows.
- Ask your GP to check your blood pressure - raised blood pressure increases the chance of further bleeding.
- Avoid heavy lifting.
What is the outlook (prognosis) for vitreous haemorrhage?
The outlook in vitreous haemorrhage depends both on the cause and on the severity. Vitreous haemorrhage resulting from posterior vitreous detachment usually has a better prognosis, particularly if the eye is otherwise normal. Where severe diabetic eye disease or macular degeneration has resulted in abnormal blood vessels, the outlook for the vision will be much less good. The outlook in penetrating eye injury is often poor.
How is vitreous haemorrhage prevented?
Prevention of vitreous haemorrhage involves preventing the underlying causes. This includes careful and regular management of diabetic eye disease (which tends to be worse in less well-controlled diabetes) and high blood pressure, and giving up smoking.
The eye should be protected from trauma during high-risk activities such as filing, grinding and hammering, using firearms and playing sports with high-speed balls, such as squash.
Dr Mary Lowth
Dr Mary Lowth
Dr Hayley Willacy